Your bathroom is wet. It’s the only place in your house where water flows freely. Yes, you have a sink in your kitchen, but unless you’re showering in the kitchen, the amount of steam, humidity and moisture produced there is miniscule compared to your bathroom. The bathroom is also one of, if not the smallest room in your house, so moisture can build up quickly. Lastly, let’s face it, odors can also build up in your bathroom.

All this adds up to one thing: your bathroom requires ventilation. Moisture and odors need somewhere to go. Otherwise, mold and water damage will occur. Building codes, in fact, require that bathrooms have some form of ventilation. In older homes, this is accomplished simply by opening the bathroom window. That works, but it’s not the most comfortable solution when temperatures rise or fall. Modern homes have exhaust fans for this reason.

Exhaust fans work by pulling moist, odorous air to the outside of the home so that fresh air can enter the bathroom. This requires two things in addition to the fan itself: electrical power and ductwork.

Thewiring for your exhaust fan can either be connected directly to an existing light switch so that when the light is on, the fan is also on, or it can be connected to a separate switch so that the fan can be operated independently. The second option is preferable because it uses less electricity when you want just the light or just the fan to be on. You may also want to consider putting your exhaust fan on a timer so that, after a long shower, you can leave it on to clear out the moisture after you’ve left the bathroom.

The ductwork attached to your fan delivers the moist foul air to the outdoors. As such, it needs to connect to the outside of the house and not another room or attic space. Otherwise, you are just moving moisture from one part of the house to another. Additionally, the ductwork should take the shortest route possible to the outdoors and have as few bends and turns as possible, so that the fan can perform with optimal efficiency.

When selecting the actual fan to install in your bathroom, the most important feature to look at is its power. Generally speaking, the larger your bathroom, the more power your fan will need to have. Measure the cubic area of your bathroom and check with the manufacturer to make sure the fan you select is rated for the amount of space you want to ventilate.

The type of fan you select will either be inline, ceiling-mounted or wall-mounted.

Inline fans are installed to the joists above the drywall of your bathroom ceiling. The only visible portion of the fan is a louvered vent that sits flush with the ceiling. Because the hardworking part of the fan resides in space above your ceiling, inline fans make very little noise and tend to be more powerful than other options.

Ceiling-mounted fans are attached directly to your ceiling rather than the joists above it. They function similarly to inline fans in terms of exporting air through adjacent ductwork. They are easier to install and replace, assuming the required ductwork is in place. They also offer a larger variety of options, including combination units with lighting in addition to ventilation.

Wall-mounted fans are installed and function just like ceiling-mounted fans, but, as the name implies, they are attached to a wall rather than the ceiling. These can be an option where logistics do not allow fan to be installed on the ceiling. Perhaps your bathroom has cathedral ceilings, no attic space above it or the ceilings are occupied by skylights or lighting. When installed on an exterior wall, these models nearly minimize the amount of ductwork required to vent the to the outside. If on an interior wall, however, more ductwork may be required to route the air up the wall, into the space above the bathroom and, ultimately, outside.

If your bathroom is undergoing a complete renovation, ventilation is not something that you want to overlook. Take the time to work an exhaust fan, along with the proper electrical and ductwork, into your renovation plan. If your bathroom does not have a window, it’s an absolute requirement, but even if it does have a window, you’ll be glad to have a fan when hot or cold weather strikes.